Like a rolling stone, singer-guitarist Llewyn Davis tumbles through the Greenwich Village folk-music scene of the '60s and onto any available couch of his friends. Oscar Isaac, in a breakout role as the title character, owns every sliver of spotlight in the Coen Brothers' most compelling character study to date. Understated and laced with the siblings' signature sardonic humor, the film explores why some talents shoot to stardom, whereas others struggle passionately and tirelessly yet never become successful artists -- and all the while, the times they are a-changin'.

The subtleties of the narrative showcase the confidence that the writer-director team has in its storytelling skill and in the audience. In the gorgeous opening scene, Davis (Isaac of "Drive" and "The Bourne Legacy") performs the melancholy "Hang Me, Oh Hang Me" at the Gaslight Cafe, which will become iconic during the "folk revival." Sadness darkens his brown eyes.

After the number, the owner of the place (Max Casella) tells Davis that a friend is waiting outside: a mysterious figure who punches and kicks him to the pavement. Ethan and Joel Coen do not offer an explanation until the film circles around to the same scene at the end, trusting viewers to care about the surly protagonist and patiently pay attention as his adventure unfolds. Blink-and-you'll-miss-it moments include Davis sauntering across the film frame as a straggly singer, guitar in hand and harmonica around his neck, gives voice to an unconventional sound in the background. The brush with Bob Dylan greatness is a grace note.

Although the Coen's "O Brother, Where Art Thou?" evokes Homer's epic poem directly, the odyssey of Llewyn Davis is at the heart of this film. His winter wanderings take him, and an orange tabby cat, all over New York City and eventually to Chicago and back. Along the way, the musician gets some bad breaks and creates his own hard luck. He has impregnated his friend's wife (Carey Mulligan plays the wife of Justin Timberlake), hitches a wild ride with a beatnik (Garrett Hedlund) and jazz musician (John Goodman), and plays one of his own songs for a recording impresario (F. Murray Abraham), who flatly states, "I don't see a lot of money here." Broke and almost broken, Davis stubbornly insists on remaining a solo act.

The moody visuals of cinematographer Bruno Delbonnel express the inner mind of the main character, and the tone grows increasingly surreal (although never as strange as that of Martin Scorsese's "After Hours"). A backstory gradually emerges that reveals Davis' stint in the Merchant Marines and a suicide, among other dramatic events. But the Coens never deliver this information in a formulaic matter. They also allow us to cringe over throwaway moments, such as when Davis takes a session gig and signs away his right to royalties, accepting a couple hundred bucks instead. The song is dopey -- and sure to become a big hit.

The Coen Brothers have crafted a minimalist film, masterful and assured in its seeming simplicity. Reteamed with executive music producer T-Bone Burnett, they honor the cinematic equivalent of what composers refer to as the space or silence between the notes. The notes they don't play -- the words unsaid, the character and plot subtleties -- make "Inside Llewyn Davis" so richly rewarding.